JPH02208762A - Memory capacity deciding device - Google Patents

Abstract

PURPOSE:To decide a memory capacity by deciding whether prescribed data written to a specific address corresponding to the capacity and data read from the said address next are the same or not. CONSTITUTION:A read/write control means 31 of a microprocessor 3 reads data Y1 and Y2 stored, for example, in a head address X2 of a head address X1, 16KB with 8KB of a memory 1, and the data are retreated once to the stack of a memory 32 in the microprocessor 3. Next, Arbitrary data Y1' and Y2' stored in the addresses of X1' and X2' of the memory 32 corresponding to the X1 and X2 respectively are written in the head address X2 of the head address X1, 16KB with 8KB of the memory 1. Next, the data Y2' and Y1' are read from the head address X1 of the head address X2, 8KB with 16KB of the memory 1, respectively, and whether the data are the same as the data Y2' and Y1' to be written, respectively, is decided. Thus, the memory capacity can be decided.

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention relates to a memory capacity determination device for an element having a rewritable memory inside, such as an IC card.
More specifically, various ICs installed via connectors
The present invention relates to a memory capacity determination device that can determine the memory capacity in a card using a simple method.

<Conventional technology> IC cards usually have rewritable memory inside, and can be connected to a computer (via a connector) as needed.
microprocessor). The computer reads information from the memory in the installed IC card, performs predetermined calculations based on this information, and transmits necessary information to the I/O.
Write to the memory in the C card.

In systems using such IC cards with rewritable memory, when an IC card is installed or inserted into the system, the amount of new information written to the card's memory exceeds the memory capacity. If this occurs, problems such as not being able to write new information to the end occur.

Conventionally, with regard to the memory capacity within an IC card, there are various types of IC cards that can be installed, and there has been no system that allows the memory capacity of each IC card to be determined at the time of installation.

<Problems to be Solved by the Invention> The present invention has been made in view of the above situation, and is a method for automatically reducing the memory capacity of the IC card when the IC card is installed or inserted into the system. The purpose is to provide a device that can make the determination.

Means for Solving the Problems> The present invention for solving the problems described above consists of an element having a rewritable memory therein, and a microprocessor that is coupled to the memory when the element is attached. When an element is installed, data at a specific address corresponding to its capacity is temporarily saved in the memory within the element, predetermined data is written to those addresses, and then data is read again from the corresponding address, and then The capacity of the memory is determined depending on whether the data matches predetermined data written first.

Function> By determining whether the predetermined data written to a specific address corresponding to the capacity is the same as the data read next from the corresponding address, it can be determined whether the corresponding address exists. Enables judgment of memory capacity.

<Example> Embodiments of the present invention will be described in detail below with reference to the drawings.

FIG. 1 is a block diagram showing an embodiment of the present invention. In the figure, 1 is the memory inside the IC card, 2 is the connector to which this IC card is installed, and 3 is the data bus DB and address bus A connected to the IC card 1 via the connector 2.
A microprocessor connected by B.

31 is a read/write control means for the memory 1, and 32 is a memory in the microprocessor, which stores arbitrary data Yl to be written to a specific address X1 in the memory 1 in the IC card.
, arbitrary data Y2 to be written to the specific address X2, etc. are stored. Reference numeral 33 denotes a capacity determining means that compares data written into the memory 1 and data read from the memory 1 to determine the memory capacity.

The operation of the device configured as described above will be explained as follows.

FIG. 2 is a flowchart showing an example of the operation performed by the microprocessor 3 when an IC card is attached to the connector 2. FIG.
2 is a conceptual diagram of the internal configuration of a memory 1 in a C card. FIG. Here, the capacity of memory 1 is 8KB.

It is assumed that it is 16KB.

First, the read/write control means 31 of the microprocessor 3 reads the starting address (for example, 8 KB) of the memory 1 (
Xi), reads the data Yl and Y2 stored at the first address (X2) of 16KB, and reads these data Yl
, Y2 are temporarily saved to the stack of the memory 32 in the microprocessor 3 (step 1.2).

Next, start address XI of 8KB of memory 1.

This XI is placed at the first address X2 of 16KB.

Arbitrary data Yl'Y2' stored in the addresses Xi' and X2' of the memory 32 corresponding to X2 is written (steps 3 and 4).

Next, start address of 16KB of memory 1 x2.8K
From the start address X1 of B, data Y2',
Yl' is read and it is determined whether the data is the same as the data Y2' and Yl' written in steps 4 and 3, respectively (step 5.6).

In step 5, if the read data is the same as Y2', it means that the first address of 16 KB exists, and the capacity of memory 1 of the inserted IC card is 16 KB.
It is determined that it belongs to KB (step 7). If the read data is different from Y2', it means that the corresponding address does not exist, and the process moves to step 6.

In step 6, if the read data is the same as Yl', it means that the first address of 8KB exists, and it is determined that the memory capacity of the inserted IC card is 8KB (step 8). .

In steps 5 and 6, if the read data is different from Y2' and Yl', it is 8KB.

The first address of each of the 16 KB does not exist, and in this case, it is determined that the IC card is not installed (step 9).

Judgments in steps 5 to 9 are made by the capacity determining means 33 implemented by software within the microprocessor 3.

When these memory capacity determinations are completed, the memory 3 of the microprocessor 3 is temporarily stored in step 1.2.
Each of the data Yl and Y2 stored in the stack No. 2 is written to the corresponding address of the memory 1 in the IC card (step 10.11), and the process ends. This step 1
By performing the processing of 0.11, it is possible to prevent the memory contents in the IC card from being destroyed by the operation for capacity determination.

In this embodiment, it is assumed that the memory capacity of the IC card to be installed is 8 KB or 16 KB, and the address for accessing the memory 1 from the microprocessor 3 is the starting address of 8 KB.

The first address is 16KB, but if you prepare more addresses to access depending on the memory capacity of the IC card installed, it will be possible to adjust the address for various memory capacities.
You can make detailed judgments.

<Effects of the Invention> As explained in detail above, according to the present invention, various IC
You can determine the memory capacity in the card with a simple operation. Therefore, various systems that handle IC cards are
By determining the memory capacity of an IC card to be attached or inserted at the time of attachment, it becomes possible to perform appropriate processing according to the capacity.

[Brief explanation of the drawing]

FIG. 1 is a configuration block diagram showing one embodiment of the present invention, and FIG.
The figure is a flowchart showing an example of the operation performed by the microprocessor when the IC card is attached to the connector, and FIG. 3 is a conceptual diagram of the memory in the microprocessor and the internal structure of the memory in the IC card. 1...Memory, 2...Connector, 3...
microprocessor, 31...read/write control means, 32...memory, 33...capacity determination means tube 1
Picture Tube 2 Figure 3

Claims (1)

[Claims] Consisting of an element having a rewritable memory therein, and a microprocessor coupled to the memory when the element is attached, the microprocessor controls the memory in the element when the element is attached. Once save the data at a specific address corresponding to the capacity, write the specified data to those addresses, then read the data again from the corresponding address, and check whether the data matches the specified data written at the beginning. A memory capacity determination device characterized in that the capacity of the memory is determined depending on whether or not the memory capacity is determined.